SAN FRANCISCO — It’s hard to visualize a water crisis while driving the lush boulevards of Los Angeles, golfing Arizona’s green fairways or watching dancing Las Vegas fountains leap more than 20 stories high. So look Down Under. A decade into its worst drought in a hundred years Australia is a lesson of what the American West could become. Bush fires are killing people and obliterating towns. Rice exports collapsed last year and the wheat crop was halved two years running. Water rationing is part of daily life. ‘Think of that as California’s future,’ said Heather Cooley of California water think tank the Pacific Institute. Water raised leafy green Los Angeles from the desert and filled arid valleys with the nation’s largest fruit and vegetable crop. Each time more water was needed, another megaproject was built, from dams of the major rivers to a canal stretching much of the length of the state. But those methods are near their end. There is very little water left untapped and global warming, the gradual increase of temperature as carbon dioxide and other gases retain more of the sun’s heat, has created new uncertainties. Global warming pushes […]